Wrist pin for reciprocating engines



Jan. 5 1926.

G. B. .OLLIER wRIsT PIN FOR RECIPROCATING ENGINES Filed Jan. 2,

patente& Jan. 5, 1926.

UNITED' STATES GUY-B. COIIIER, OF KINDEBHOOK, NEW YORK.

wus'r rnf ron nncrocnrme mames.

Application filed January 2, 1924. Serial No. &83,877.

To alt whom itmay conce7'n.'

Be -it known that I, GUY B. "ConLI-m, a citizen of the ,United States, residing at Kinde-hook, in "the county of Columbia and State of New York, have invented certain new and useful Imp'rovenents in Wrist Pins for Reciprocating Engines; and I do hereby declare the followin to be a full clear,

and exact description o the invention, such as will enable others skilled in the art to which it app'ertains to nake and use the same.

The present invention relates to wrist pins for reciprocating engines and' more particularly to wrist pins employed in connection with internal conbustion motors.

It is well recognized that vibration in an internal combustion motor may be material-- l reduced through reduction in weight of tlie reciprocating parts and with this end in View pistons and` connecting -ods of light weight metals and. alloys have been constructed. No substantial reduction in the weight of the wrist pin has been made, however, as these pins are made of steel alloy n the form of a thick walled tube averaging one inch in diameter and approximating in length the diameter of the piston. Itwill be evident that the weight of the wrist pin is a considerable factor-'in determining the total weight of the pisten. unit, especially when the piston is made of a light weight metal alloy.

Theobject of the present invention is ,to redesign and inprove wrist pins with a View to substantially reducing the weight. With this object in View, the several features of the invention consist in certain novcl features'of Construction, combinations and arrangements of parts hereinafter described' and claimed, the advantages of which will be obvious to those skilled in the art from the following description. p In the accompanying drawings illustrating the preferred form of the invention, Fig. l represents a section in elevation of a piston with the improved wrist pin embodied therein; Fig. 2 is an elevation of the pisten showing an elevation of the wrist pin; Fig.

3 is a sectional elevation of the wrist pin re` moved from the pston; Fg. 4 s an end view partly in section of the 'pin shown in` Fig; 3; Figs. 5 and 6`represent a partial elevaton and end view, respectively, of a Inetallic tube enployed for the production of the wrist pin; Figs. 7 and 8 represent an elevation and plan of !in annulus adapted to be inserted within the tube; Figs. 9 and 10 represent a partial elevation and plan View of a modified form of wrist pin embodying certain principles of the invention; and F igs 11'and'12 represent a partial elevation and end wcw of a still further modification of the invention.

The illustrated e'nbodinent of the invention shows a pisten 10 of conventional form having oppositely dis'posed bosses 12 and 14 projecting inwardly for the support of the wrist pin. 'A collecting rod indicated at 16 is operatively connected with the pisten through a wrist pin indicated generally at 18. The hub portion 20'of the connecting rod is received between the opposite faces of the bosses 12 and 14, leaving comparatively narrow intervening regions 21. According to the present invention, the regions 21, forning the gapbetween the hub 20 of the connecting rod and the piston .bo'sses, are bridged in each case by an annuwalls throughout its length except at two regions intermediate the ends and correspondng to theregions separating the connecting rod from the bosses ofthe pisten, at i which regions the walls of the wrist pin are substantially thickened to provide Walls having a thickness at these regions which may average two and one-half to four times the thickness of the walls throughout the remainder of the shell. It has been found as the result of extended research and mathenatical`calculation that the total stresses 'excrted upon the wrist pin at the regions 21 far exceed the stresses at other points throughout the length of the pin and that if the wrist pin has the requisite strength iu cross section at these regions it may be made with relativel'y thin walls throughout the remaining por tion of its length.

The annulus or thickened portion of the wrist pin may be varied, as indicated in 'Figs '1 and' 3, the annulus 23 shown in Fig.

1 being ad pted for service relatively lighter ends, oi' t than the annulus indicated at' 28 in Fig. 3. The wrist pin indicated generally in Figs.

1 and 3 may be formed by removing a purtion of the material from a relatively thick walled tube, leavin the thickened ortions project-in# intoethe nterior interme iate the he pin may preferably be forn'ed ns- V indicated in Figs. 5 to 8 inclusive. In this Construction, a thin walled tubing of uniform 'internai and external diameter as, 1ndicated generaily at 30 is adapted tohave a ring or annulus 32 received therein After being located 'in the proper positionwith respect to the tube, the annulus is welded thereto to form an integral 'part of. the tube and the whole may then be finished in any suitable manner provide the wrist in approximutely as shown in Figs. 1 an 3.

The wrist pin is the equivalent of a beam fixed atopposite ends and having a load applied uniformly' over its central region, that is the region embraced by the hub of the connect-ing rod. This load varies, however, throughout the circumference of the pin and is at its maximum ut the top and bottom of the pin, these regions of maximum Stress being indicated in Fig. 10' at 41 and 42 andin Fig. 12 at 43 and 44. In order to provide the re uisite 'strength throughout these regione an avoid the use of unnecessary material throughout the remainder of 'the tube; the letter may be construeted as indicated in Figs; 9 to 12 inclusive. As

shown in Figs. 9 and 10, a tube is provided having an elliptical internal bore providing e wail which is thickest at the to and, bottom portions of the tube, gradual y decreasing until it reaches a minimum at the side ortions of thetube, as indicated at 45 in* The improved -form of wrist pin may Conveniently beretained in assembled relaton withinthe piston as indicated in Fig. 1, through the employment of looking rings -which are received in grooves forn'ed within the bosses 12 and 14 and engage with oppositeends of the wrist pin to hold the latter in place. .In the event that this type of Construction is employed, it is desirable to insert a bushing 52 between the wrist 'pin and the piston boss in addition to the usual bushing 54 inserted within the hub 20 of the connecting rod. n lace of the 60, which'is threaded in the boss o Construction shown in Fig. 1, t

V\ e wrist pin may be retem'ed n place by a lockin pin the claims and may greatest thickness at the i the wrist pin to lock the letter against rotative as well aslongitudinal movement. This type of looking Construction must necessarily -be used in the event that the general form of wrist `pin shown in Figs. 9 to 12 is used, as this type of pin must be permanently held in position with the regions 41 and 42.positiened respcetively at the top' and bottom of the pin.

a' It will be evident to those skilled in the art thatthe form of wrist pin described in the foregoing specification provides the requisite strength throughout the regions where such strength is necessary but s relieved of all sur-plus material throughout the remaining portions of the pin. The wrist pin in eifect consists of tworings of suflieientwidth to extend throughout the regions 'of greatest Stress with intervening .relatively thin webs or walls, which serve the ' urpose of holding the rings in the desired operative relation and of withstanding the relatively small stresscs which occur in the length of the wrist pin outside the regions of greatest Stress.

While it is preferred to employ the specic Construction and arrangenent of parte shown and described, it will be understood that this eonstruction and artan ement is not essential except' so far as s eci ed in the be chan e or. modified without departng fr in t e broader features of the inventio 'The invention having been described, what is claimed is:

1. A piston assembl for a. 'eciprocating engine comprisin a ollow piston having internal bosses a a ted to receive a wrist in, a connecting ro ositioned between the piston and extends at its free end through ioo osses and havng re atively small regions of clearance upon opposite sides, e wrst pin extendi'ng through the connecting rod and received at o posite ends within the piston bosses, an a. reinforcing rib' pr annulus formed integral with the wrist in and bridging each region of clearance etween the connecting rod and the piston boss.

2. A'piston assembly for a reciprocating engine comprising a hollow piston, internal bosses for-med upon the piston, a eonnecting rod supported etween the bosses, an annulus' eonnecting each side of the rod with the piston boss and bridging the space therebetween, and a relatively thin cylindrical wall having the same outer diameter as that of the annuli, connecting the two annuli and serving to retain the annuli in proper relation and withstand minor stresses..

3. A wrist pin conprising a` tubular shell hav ng e uniforin external diameter and having annular reinforcing rbs extending inwerdly therefrom intermediate the ende 1 &me between th connctingro mames and dapted to bridge the regione ef cleard and'the pis-,ton 'when the pin is assembled with the pisten and cqmecting rod.

4. A pisten assembly for reciprocating engines comprsing a hollow pisten, a coh fiting rod, a wrist pin passing through the connecting r'od and received at opposite ends in thepiston, an annular refi forcement fol-med u on the interior ef the wrist pin adj cent t e region:: of eiearme between the-connecting red and; 'the pishat&

and means for retaining the w'st in'. assmbled relation within the pisten.

GUY B. Co i-Im. 

